I cut the ballsave time from 15 to 6 on my game; that reduces the excessive multiballs. It also seems that chop self-disables at some point during Ho1K corpses.
The multiballs following modes can be lucrative - Demonoid and Dragula - can exploit the ramp after trapping up on right. You have to make sure to collect 4x jackpot from Spaulding to make it worthwhile.. if you blow out the UPF, shoot left orbit to try again before finishing the mode - not worth finishing these at 1x jackpot unless you're Hellbound. Mind the timer though! Also most post-mode multiballs have other shots that are worth big points.. Demonoid - relight all the lamps again... What! - shoot the pussy liquor shot for ? millions (ramp resets timer), also the hurryup on left. Radio - keep collecting 1-2-3 for characters and points... Dragula has the car parts if you skip video mode for the multiball instead, these go into bonus so play Dragula early.
Biggest reason for crap mode scores: not getting 4X from Spaulding, not hitting LDG to boost JP during ensuing multiball, not focusing on mode-specific shots during multiball. The rules are pretty complex - check Fawzma's blog for mode details.